bash¶

Trapping signals in bash scripts¶

In bash scripts, you can use the trap command to catch and handle signals. This is useful for cleaning up resources or performing specific actions when your script receives certain signals.

Trapping SIGTERM signal for clan shutdown

#!/bin/bash

# Function to handle shutdown
shutdown() {
    echo "Cleaning up before exiting..."
    exit 0
}

trap shitdown SIGTERM

# Simulate a long-running process
echo "PID: $$"
while true; do
    echo "Running..."
    sleep 1
done

In this example, when the script receives a SIGTERM signal, it will execute the cleanup function before exiting.

Running the scriptKilling the script

$ bash trap.sh
PID: 37613
Running...
Running...
Running...
Cleaning up before exiting...

$ kill 37613

Print the current script¶

It is often useful to print the content of a script before the output of the script itself, for debugging or logging purposes.

This can be done by using the special variable $0, which contains the name of the script being executed.

Print current bash script

$ bash test.sh 
#!/bin/bash

cat $0

echo "Hello"
Hello